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Computations of distributed systems are extremely difficult to specify and verify using traditional techniques because the systems are inherently concurrent, asynchronous and nondeterministic. Furthermore, computing nodes in a distributed system may be highly independent, and the entire system may lack an accurate global clock. In this thesis, the author develops an event-based model to specify formally the behavior (the external view) and the structure (the internal view) of distributed systems. The specification technique has a rather wide range of applications. Examples from different classes of distributed systems, including communication systems, transaction-based systems and process control systems are demonstrated. Both control-related and data-related properties of distributed systems are specified using two fundamental relationships among events: the precedes relation, representing time order; and the enables relation, representing causality. No assumption about the existence of a global clock is made in the specifications. The correctness of a design can be proved before implementation by checking the consistency between the behavior specification and structure specification of a system. Moreover, since the specification technique defines the orthogonal properties of a system separately, each of them can then be verified independently. Thus, the proof technique avoids the exponential state-explosion problem found in state-machine specification techniques.